Thixotropic adhesive gel

ABSTRACT

A water based thixotropic adhesive gel is disclosed which consists essentially of: water; partially hydrolyzed polyvinyl alcohol, or wherein a portion of the polyvinyl alcohol is replaced with polyvinylpyrrolidone; a water-soluble high viscosity thickening agent polymer which is compatible with the polyvinyl alcohol and which imparts thixotropic properties to the gel; a water-soluble plasticizer for the polyvinyl alcohol; and a watersoluble defoamer in proportion of ingredients so that the viscosity of the adhesive will break down when a flexible tube or squeeze bottle dispenser is finger-pressed and have a sufficiently low viscosity to allow for easy extrusion from an orifice having a diameter of about 0.06 to 0.12 inches. When pressure is released, after the desired amount of adhesive has flown out of the dispenser, the adhesive quickly reverts to very close to its original gel state so that it will not run on a vertical surface on porous and semiporous surfaces such as paper. An article of manufacture is also provided whereby the adhesive gel containing the above ingredients is in a flexible dispenser from which the adhesive can be dispensed by finger-pressure.

This .Iadd.is a reissue of application Ser. No. 08/150,435, now U.S.Pat. No. 5,322,880, which .Iaddend.is a divisional of application Ser.No. 07/976,553 filed on Nov. 16, 1992 now U.S. Pat. No. 5,284,897.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a clear, thixotropic, water based generalpurpose, polyvinyl alcohol adhesive gel for porous and semiporoussubstrates such as paper, card board, cloth and wood.

2. Background Art

Many different general purpose adhesives are available for adheringporous and semiporous substrates such as paper. However, such adhesiveshave shortcomings for use in projects which are performed on wall boardsand other vertical surfaces such as in a class room by young children.

The adhesive gels of this invention consist essentially of: water; apartially hydrolyzed polyvinyl alcohol: a water-soluble thickening agentpolymer which is compatible with polyvinyl alcohol: a water-solubledefoamer: and a water-soluble plasticizer for the polyvinyl alcoholwhich does not destroy the clarity of the gel. Optionally, otheringredients can be added which do not destroy the advantageousproperties of the gel. Compatible preservatives are generally added tothe gel.

The Handbook of Water-Soluble Gums and Resins by R. L. Davidson, 1980 byMc Graw-Hill. Inc. pages 20-20 discloses partially hydrolyzed polyvinylalcohol as an adhesive and page 20-18 discloses the use of certaingelling agents to control penetration of polyvinyl alcohol solutionsinto porous substrates or to prevent run-off of coating by dippingwhereas page 20-19 of that reference discloses the use of an antifoamagent with polyvinyl alcohol. Pages 21-15 and 21-16 of the Handbookreference describe adhesive properties of polyvinylpyrrolidone (PVP).Among other shortcomings, these references do not mention the use ofthixotropic agents with polyvinyl alcohol nor proportions of ingredientsused in obtaining the advantageous properties of this invention.

U.S. Pat. No. 3,442,845 of May 6, 1969 to P. Columbus et al. relates topolyvinyl acetate adhesives which are redispersible in cold or hotwater. The adhesive compositions of the 845 patent use polyvinylalcohol. water-soluble gums, and cellulose ethers as anti-coalescingagents for the polyvinyl acetate. Propylene glycol and other polyhydroxycompounds are mentioned as plasticizers for polyvinyl alcohol. However,among other shortcomings in relation to the adhesive gel of thisinvention, the adhesive of the 845 patent does not have the thixotropicproperties, clarity, or rate of set of the adhesive gel of thisinvention.

U.S. Pat. No. 4,251,400 of Feb. 17, 1981 to P. Columbus also relates toa polyvinyl acetate adhesive which is redispersible in hot and coldwater in the dried film form and which uses polyvinylpyrrolidone and anonvolatile, water-soluble, plasticizer as the anti-coalescing agent. Inaddition to the polyvinyl acetate and polyvinylpyrrolidone that patentalso mentions the use of polyvinyl alcohol, propylene glycol, as well aswater-soluble ethers in the adhesive composition. The adhesive of the400 patent lacks many of the properties of the adhesive gel of thisinvention such as rate of set, clarity, and the thixotropic properties.

A mucilage containing about 83% of water: 14% of partially hydrolyzedpolyvinyl alcohol; 0.2% of a water-soluble polyalkoxylated polyetherdefoamer; 1.8% of propylene glycol and a total of about 0.25% of boricacid and citric acid as thickeners is a well known commercial product.Again, this mucilage lacks properties of the adhesive gel of thisinvention such as the thixotropy and wet tack.

European Patent Application Publication Number 0210052 to .[.Locktire.]..Iadd.Locktite .Iaddend.which was published on Jan. 28, 1987 relates tovarious tubes for dispensing reactive adhesives such as cyanoacrylate ata rate of one or two drops at a time. The patent mentions resilientplastic tube dispensers and broadly states that the adhesive can bethixotropic.

SUMMARY OF THE INVENTION

In one aspect of the invention, a clear, water based polyvinyl alcoholadhesive gel is provided which contains a water-soluble high viscositythickening agent polymer which provides thixotropic properties to thegel, a water-soluble plasticizer for the adhesive polymer, and awater-soluble defoamer. Due to its thixotropic properties, the viscosityof the adhesive will break down when a flexible tube or squeeze bottleis finger-pressed and have a sufficiently low viscosity to allow foreasy extrusion from a small orifice such as one having a diameter ofabout 0.06 to 0.15 inches. When pressure is released after the desiredamount of adhesive flows out of the orifice, the adhesive quicklyreverts to very close to its original gel state so that a horizontalline of the gel will not run when applied to a vertical surface of aporous substrate such as paper.

In another aspect, the adhesive gel is crystal clear or transparent.

In still another aspect, the adhesive gel has a strong wet tack with alow rate of set. This holds a second substrate in position with a firstsubstrate in a vertical plane after contact of the substrates with thegel while permitting sliding and repositioning of the second substratefor a prolonged period of time prior to formation of permanent adhesionand fiber tearing bonds due to setting of the adhesive.

In a further aspect of the invention, a portion of the polyvinyl alcoholadhesive polymer is replaced with polyvinylpyrrolidone.

In still another aspect, an article of manufacture is provided wherebythe adhesive gel of this invention is contained in flexible dispenserhaving an orifice of about 0.06 to 0.15 inches in diameter from whichthe adhesive can be dispensed by fingerpressure.

In still a further aspect, the orifice of the flexible dispenser isinterrelated with the thixotropic index and viscosity of the gel topermit extrusion of the gel from the flexible dispenser by applyingfinger-pressure to the dispenser and wherein the extruded gel forms abead which does not run when applied in a horizontal line on paper in avertical plane.

Additional aspects of the invention will be evident from reading of theentire specification and claims.

Advantages of the invention include: (1) The adhesive gel will not runwhen applied to porous and semiporous vertical surfaces and will notspill when used as a general purpose school glue. (2) The adhesive gelextrudes easily and in a steady stream from a small orifice when aflexible tube or squeeze bottle is finger pressed and reverts to gelwhen finger-pressure is released. (3) The combination of adhesive geland small dispenser opening, e.g. from about 0.06 inches to 0.15 inchesin diameter, minimizes or eliminates wrinkling of paper upon drying ofthe adhesive. (4) The adhesive in a clear resilient plastic dispensercan be viewed within the dispenser as clear which may include a tint ofcolor (5) The adhesive gel is preferably crystal clear or has a clearcolored tint and provides a clear dry film. (6) The dry adhesive film isflexible and will not crack on bending. (7) The adhesive gel has astrong wet-tack to hold paper surfaces together while drying. (8) It hasa long rate of set so as to permit sliding and positioning of substratesbefore fiber tearing permanent adhesive bonds are developed. (9) Theadhesive gel as well as dried films thereof will launder-out in hot orcold water. (10) The adhesive gel can be tinted easily with non-toxicwater-soluble dyes. (11) The adhesive gel is non-toxic and is not anirritant to the skin and eyes as defined in the Federal HazardousSubstances Act.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation of a flexible tube dispenser containing theadhesive gel of this invention.

FIG. 2 is a plan view of that shown in FIG. 1.

FIG. 3 is a side elevation of a flexible squeeze bottle containing theadhesive gel of this invention.

FIG. 4 is a plan view of that shown in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a conventional, flexible plastic, low density, polyethylenetube dispenser 10 having a clear hollow tube portion 12 which has acapacity of about 3 fluid ounces and a crimped, closed end 14. The wallthickness of the polyethylene is 0,018 inches. The closed end beyondcrimp 14 has an extending flap 16 which has a cut out portion 18 so thatthe dispenser 10 can be hung up and displayed or stored. The dispensingend 20 of tube 12 has a conventional screw threaded dispenser closurecap 22 which can effect opening and closing of orifice 26 by holding cap22 in place while twisting cap end 74. Dispenser 10 contains adhesivegel 40 of this invention and the adhesive 40 in contact with tube 12provide a clear appearance when the dispenser is viewed.

FIG. 2 more clearly shows dispenser opening 26 at the end of cap 24.

FIG. .[.2.]. .Iadd.3 .Iaddend.shows a clear, conventional, flexibleplastic. low density polyethylene squeeze bottle 30 which has a capacityof 4 fluid ounces. Bottle 30 has neck portion 32 which has an open endwith conventional screw threads, not shown. Conventional dispenserclosure cap 22 has internal screw threads which mate with those on neckportion 32. Cap 22 can effect opening and closing of orifice 26 bytwisting of the cap end 24 as with FIGS. 1 and 2. Dispenser bottle 30contains clear gel adhesive 40. The clarity or transparency of theportion of bottle 30 containing the adhesive 40 is similar to that ofFIG. 1.

FIG. 4 more clearly shows dispenser opening 26 at the end of cap 24.

In place of a flexible plastic tube or squeeze bottle, other dispenserssuch as deformable, ductile, metal tubes can be used; although suchtubes do not provide for clarity.

The preferred adhesive gels of this invention are clear. The term"clear" is used herein in contrast to opaque. The term "clear" includestransparent, i.e., see through, as well as translucent.

The term "water-soluble" as used herein refers to solutions of eithersolids or liquids which are soluble or miscible in water to provide asolution which is clear at the concentration employed.

The "thixotropic index" is the difference in viscosity for the gel froman undisturbed state to that wherein the gel is being displaced byforce. The term "thixotropic" as used herein is also meant to coverpseudoplastic. The thixotropic index used in this invention permitsextrusion of the gel from the dispenser opening by use offinger-pressure on a flexible dispenser such as a tube or squeezebottle. The adhesive rapidly reverts to a higher viscosity afterextrusion from the orifice. The adhesive gel does not run, i.e. spreadwithout the application of external force, when applied to paper in avertical plane when extruded through the small orifices of thedispesnsers used in this invention, although there can be a slightamount of creep such as that of less than 0.15 inches and preferablyless than 0.1 inches. The smaller orifices in the dispensers such asthose of less than 0.1 inches in diameter, e.g., 0.073 inches indiameter minimize any creep.

The thixotropic index for the adhesive gel of this invention varies fromabout 1.5 to 4.5 preferably about 1.5 to 4 and particularly 1.8 to 2.5.The thixotropic index used herein is obtained by dividing the viscosityreading of the gel at 2 RPM (revolutions per minute) by the viscosityreading at 20 RPM by use of an RVF Brookfield viscometer using a number6 spindle at 25° C. The viscosity readings are taken after the gel hasbeen at rest e.g. undisturbed, for a period of time such as 12 hoursafter any agitation or other disturbance of the gel structure. It shouldbe noted that different methods for measuring thixotropic index willgive different results.

The adhesive gels of this invention have a viscosity of about 30,000 cps(centipoise) to 100,000 cps at 25° C. and preferably about 50,000 cps to90,000 cps at 25° C. as measured with an RVF Brookfield viscometer byuse of a number 6 spindle at 2 RPM (revolutions per minute). Whenmeasured at 20 RPM with an RVF Brookfield viscometer at 25° C. by use ofa No. 6 spindle, the viscosity is about 15,000 cps to 60,000 cps,preferably about 20,000 cps to 40,000 cps, provided that the thixotropicindex is within the ranges set forth herein.

The major ingredient in the adhesive gel of this invention is water. Thequantity of water can vary over a broad range such as that from about70% to 93% by weight of the adhesive gel, preferably 75% to 93% andparticularly from about 80% to 90% by weight thereof.

POLYVINYL ALCOHOL ADHESIVE POLYMER

The adhesive agent used in this invention is partially hydrolyzedpolyvinyl alcohol or such polyvinyl alcohol with polyvinylpyrrolidone(PVP) wherein the PVP replaces up to about half of the polyvinylalcohol. The polyvinyl alcohol will normally have a molecular weight ofabout 25,000 to 100,000 and preferably about 40,000 to 80,000. Theviscosity of the polyvinyl alcohol can vary over a wide range such asthat of about 5 or 6 cps, which is referred to in the art as lowviscosity, to 40 to 50 cps, which is referred to in the an as highviscosity as measured with an LVF Brookfield viscometer using a number 1spindle at 60 RPM at 20° C. for a 4% aqueous solution. The preferreddegree of hydrolysis for the partially hydrolyzed polyvinyl alcohol is87% to 89%.

The PVP can have a molecular weight, expressed as a K value, which vanesover a wide range such as that of a K value of about 26 to 100.

The quantity of polyvinyl alcohol or polyvinyl alcohol together with PVPin the gel can vary over a wide range such as that of from about 5% to25% by weight of the adhesive gel, preferably from about 5% to 20% andparticularly 10% to 15% by weight of the adhesive gel.

THE HIGH VISCOSITY THICKENING AGENT POLYMER

The high viscosity thickening agent polymer can be any watersolublethickener polymer which is compatible with polyvinyl alcohol and whichimparts thixotropic or pseudoplastic properties within the thixotropicindex and viscosity ranges of the adhesive gels of this invention. By"compatible" we mean miscible in that it does not cause separation ofthe ingredients in the gel. Illustrative of the high viscositythickening agent polymer there can be mentioned the sodium salt ofcarboxymethylcellulose, also referred to herein simply as CMC. sodiumalginate, and xanthan gum. The quantity of the thickener is that whichis sufficient to provide the adhesive gel with the desired thixotropicindex and viscosity. Such quantity will generally vary from about 0.5%to 1.5% by weight of the adhesive gel and preferably from 0.85% to 1.25%by weight of the adhesive gel.

THE WATER-SOLUBLE PLASTICIZER

Any water-soluble plasticizer for the polyvinyl alcohol which does notdestroy the clarity of the gel is suitable for use in this invention.Such plasticizers soften the polyvinyl alcohol, make the adhesivestickier, and assist in making the dried film easier to wash out ofclothing. Illustrative of such plasticizers there can be mentioned:alkanes having from 2 to 5 carbon atoms and 2 to 3 hydroxyl groups suchas: propylene glycol; glycerol; ethylene glycol; and diethylene glycol;although ethylene glycol and diethylene glycol can have some toxicproperties. The quantity of the water-soluble plasticizer is that whichis sufficient to plasticize the polyvinyl alcohol and will generallyvary from about 0.5 to 3% by weight of the adhesive gel.

THE WATER-SOLUBLE DEFOAMER

Conventional water-soluble defoamers can be used in this invention suchas the polyalkoxylated polyethers e.g., butoxy polyoxyethylene-propoxylpropylene glycol. Silane defoamers can also be used but they canadversely affect transparency of the gel. The quantity of the defoameris that which is sufficient to eliminate air bubbles in the gel in aconcentration which destroys the clarity of the gel. Generally, thequantity of the defoamer varies from about 0.05% to 0.35% by weight ofthe gel composition. The defoamer also maintains density of the gel,prevents excessive foam in the manufacturing process, and facilitatesfilling of the dispensers with the gel.

In operation of the dispenser, the cap end 24 is twisted so as to openthe orifice 26 and finger-pressure between the thumb and forefinger orthe thumb and fingers is used to dispense the gel 40 from the dispensertube 12 or dispenser squeeze bottle 30 on to a substrate such as paper.The dispenser cap orifice 26 has a diameter of about 0.06 to 0.15inches, preferably 0.07 to 0.10 inches and particularly about 0.07 to0.08 inches. The thixotropic gel adhesive 40 flows out of the caporifice 26 in a steady stream on being finger-pressed due to itsthixotropic properties in spite of its high viscosity in the undisturbedstate. The dispensing opening need not be circular, provided that suchopening has a cross section which in relation to the thixotropic ratioand viscosity of the gel permits extrusion of the gel by finger-pressureon the flexible dispenser while a bead of the extruded gel in ahorizontal line on a vertically mounted sheet of paper does not run. Thearea of such opening should be from about .[.0.011 to about 0.12.]..Iadd.0.0028 to about 0.018 .Iaddend.square inches.

When applied to a substrate in the vertical plane, the gel does not runand has a minimum amount of creep due to the thixotropic properties ofthe gel. Any such creep is generally less than 0.15 inches and moreoften less than 0.1 inches. Due to the ability of the thixotropic gel tobe applied through a small dispenser opening, a thin glue line can beprovided on a first substrate such as construction paper which minimizesthe amount of adhesive as well as wrinkling of paper upon drying. When asecond .[.substrates.]. .Iadd.substrate, .Iaddend.such as a second pieceof construction paper is pressed over the first piece in order to beadhered thereto, the high tack of the gel holds the second substrate inplace on the vertical surface. The slow rate of set permits a prolongedperiod of time for positioning the second substrate such as by slidingof the second surface over the first before fiber tearing adhesive bondsdevelop between the two substrates which permanently hold the pieces inplace.

In order that those skilled in the art may more fully understand theinvention presented herein, the following examples are set forth. Allparts and percentages in the examples, as well as elsewhere in thisapplication, are by weight, unless otherwise specifically stated. Also,set forth below are procedures for determining "wet tack" and "rate ofset".

PROCEDURE FOR DETERMINING WET TACK

This procedure uses blocks of Grade 1 or Grade 2 white pine with eachblock being 2 inches long, 0.75 inches high and 1.75 inches wide. Thegrain of the wood is parallel to the length of the block and the sideswhich are 0.75 inches high and 2 inches long are planed and smooth. Suchsides are referred to herein as test sides. Each test side thereforprovides a surface of 1.5 square inches.

A series of tests are performed with the above described blocks of woodwith two blocks being required for each test. In each test an eye screwis placed in the center of one of the test sides of each block. Geladhesive is then placed on the opposite side of the eye screw of one ofthe test blocks so that it covers the entire 1.5 square inches ofsurface. The test side of the second block opposite the second block eyescrew and the side of the first block having the glue thereon arepressed against each other in sliding relationship while being placed inregister so that the edges of one block do not extend beyond the edgesof the other. A scale is attached to the eye screw of the first blockwhereas a weight is attached to the eye screw of the second block. Thescale is then lifted upwardly by the operator and the two blocks arelifted vertically so as to lift the weight. Thus, The operator lifts thescale by hand which in turn lifts the first block through the eye screw.This in turn lifts the second block due to the wet tack of the adhesivewhich in turn lifts the weight which is attached to the second block eyescrew. This test is repeated with clean blocks of wood and the weight isincreased each time until the adhesive between the two blocks fails tolift the second block and its attached weight. The last weight which waslifted in this test is referred to as the quantity of wet tack or simplywet tack of the adhesive. This test measures the wet tack in a directionwhich is perpendicular to the adhered surfaces. In spite of the lengthydescription of this test, it can be performed, and for reliability isperformed, rapidly by the operator. The glue, when the wet tack ismeasured between the blocks of wood is very close to the physical andchemical condition of the glue when it left the dispenser orifice. Thewet tack is a measure of what is often referred to as the grabbing powerof the adhesive. A minimum amount of wet tack is needed when gluing.[.on.]. .Iadd.one .Iaddend.substrate to another in a vertical plane,otherwise, the substrate which is not held in place but rather dependson the wet glue for positioning would slip off of the vertical surfaceof the first substrate. The wet tack of the gel of this inventionpreferably vanes from about 225 g per square inch to over 600 grams persquare inch and preferably from about 250 to 500 grams per square inch.

PROCEDURE FOR DETERMINING RATE OF SET

Determinations for the rate of set are performed on a white paper pad. Aglue line is placed on smooth white paper of a 5.5×8.5 inches paper pad.The single glue line is placed in about the middle of the pad parallelto the length of the paper. This glue is then spread evenly by the useof a No. 22, WIRE-CATOR which is supplied by the Leneta Company. TheWIRE-CATOR is also referred to as a wire wrap rod. The WIRE-CATOR drawsdown a uniform thickness of film from the single glue line. Use of theNo. 22 WIRE-CATOR draws down a glue line to a thickness of 1.5 rail.

A second sheet of the same paper has one of its narrow ends raised sothat it can be grasped by the fingers. The second sheet is pressed overthe first sheet. The two pieces are then slowly pulled apart by liftingthe raised end of the second sheet and holding the first sheet down inplace. The time that it takes to encounter fiber tearing bond is therate of set. The preferred rate of set for the gels of this invention isfrom about 16 seconds to 35 seconds and preferably from about 18 to 32seconds.

The values for both the wet tack and rate of set recited herein areobtained at 25° C. and a relative humidity of 35%.

EXAMPLE 1

This example shows the composition, preparation and properties of anadhesive gel of this invention as well as use of an article of thisinvention.

    ______________________________________                                        Ingredient         Parts By Weight                                            ______________________________________                                        Deionized water    83.51                                                      Polyvinyl alcohol.sup.1                                                                          13.33                                                      Sodium salt of     1.00                                                       Carboxymethylcellulose.sup.2                                                  DEFOAMER.sup.3     0.25                                                       Ethyl parahydroxybenzoate                                                                        0.05                                                       Benzoic Acid       0.10                                                       Propylene Glycol   1.75                                                       Blue dye.sup.4     0.01                                                       ______________________________________                                         .sup.1 VINOL 523 which is a partially hydrolyzed polyvinyl alcohol            supplied by Air Products and Chemicals, Inc.                                  .sup.2 CMC 7HX4 which is supplied by the Aqualon Company of Wilmington,       Delaware.                                                                     .sup.3 DEFOAMER 622 which is a monofunctional polyalkoxylated polyether       defoamer supplied by the Thomas W. Dunn Corp of Ridgefield, N.J.              .sup.4 No. 5601, FD&C Blue No. 1 which is supplied by Warner Jenkinson        Cosmetic Colors of South Plainfield, New Jersey.                         

The adhesive of Example 1 was prepared by slowly adding the polyvinylalcohol and CMC to water under fast agitation in a jacketed tankequipped with agitators. The CMC is preferably dry blended with aportion of the polyvinyl alcohol before addition to the water. Thedefoamer was then added. A small portion of the total amount of water inthe gel can be obtained from steam condensation when the mixture isheated in contact with steam. The ethyl parahydroxybenzoate and benzoicacid were then mixed in the composition and the temperature of themixture was raised to 85° C. to 90° C. with slow agitation for about 15to 20 minutes until the composition was smooth and homogeneous. Thecomposition was then cooled to 50° C. with continued slow agitation. Theblue dye was then added which had been prepared in advance by mixing 2parts of the dye with 98 parts of water. Mixing was continued until thebatch color was uniform.

The adhesive was then filled into 3 fluid ounce clear, low densitypolyethylene tubes 12 having a cap 22 and nozzle 24 and opening 26 of0.073 inches in diameter. After filling, the back end of tubes 12 areheat sealed to form a crimp 14 having flap 16 extending therefrom asshown in .[.Fig Land.]. .Iadd.FIG. 1 and .Iaddend.FIG. 2. The portion ofthe tube 12 in direct contact with the gel 40 was transparent with aslight blue tint. The portion of tube 12 which was not in direct contactwith the gel was translucent.

All of the examples set forth herein were performed in much the samemanner as with EXAMPLE 1.

The adhesive gel of Example 1 was transparent with a blue tint, easilydispensed with finger-pressure from the resilient plastic tube 12 havingan orifice 26 of 0.073 inches diameter. It had wet tack of 435 g (grams)per square inch and a time of set of 25 seconds. It was free of airbubbles, and when dispensed from such tube and orifice on to a sheet ofpaper held vertically, it formed a uniform, thin, horizontal bead ofadhesive which did not run and formed fiber tearing adhesive bonds ondrying to a clear film. The gel can be dispensed in a steady streamthrough the dispenser orifice. The strong wet tack held a second sheetof paper in place on the vertical surface while the lengthy time of setpermitted sliding and repositioning of the second sheet on the firstbefore permanent adhesive bonds were formed. The gel washed out ofclothing both before and after drying. This product exhibited all theadvantages set forth in the hereinabove Summary of Invention. It had athixotropic index of about 2. The viscosity of the adhesive gel whenmeasured at 25° C. with an RVF Brookfield viscometer with a No. 6spindle was as follows:

.[.Initial ly,.]. .Iadd.Initially, .Iaddend.after manufacture, and at aspeed 2 of RPM, a viscosity of 50,000 to 60,000 cps.

Initially, after manufacture, and at a speed of 20 RPM, a viscosity of24,000 to 28,000 cps.

After standing for about 12 hours and at a speed of 2 RPM, a viscosityof 70,000 to 80,000 cps.

After standing for about 12 hours and at a speed of 20 RPM, a viscosityof 30,000 to 40,000 cps.

After one month from manufacture, the viscosity was not over 100,000 cpswhen measured at a speed of 2 RPM. The adhesive of this invention had apH of 4.8.

EXAMPLE 2

This example provides another formulation having the advantageousproperties of this invention and illustrates the use of a lowerviscosity polyvinyl alcohol. The blue dye, CMC and defoamer were thesame as in EXAMPLE 1.

    ______________________________________                                        Ingredient         Parts By Weight                                            ______________________________________                                        Deionized water    76.84                                                      Blue dye           0.01                                                       Polyvinyl alcohol* 20.00                                                      CMC                1.0                                                        Defoamer           0.25                                                       Ethyl parahydroxybenzoate                                                                        0.05                                                       Benzoic acid       0.10                                                       Propylene glycol   1.75                                                       ______________________________________                                         *VINOL 205 which is a product supplied by Air Products and Chemicals, Inc                                                                              

This gel had a viscosity of 67,500 cps at 2 RPM and 21,000. cps AT 20RPM when measures at 25° C. with a Brookfield RVF viscometer having aNo. 6 spindle. The thixotropic index was 2.4 and it had a wet tack of250 g per square inch.

EXAMPLE 3

This example illustrates the use of smaller quantities of the polyvinylalcohol and CMC which produced product having the advantageousproperties of this invention.

    ______________________________________                                        Ingredient      Parts By Weight                                               ______________________________________                                        Deionized water 85.4                                                          Blue dye        0.01                                                          Defoamer        0.25                                                          Polyvinyl alcohol*                                                                            11.6                                                          CMC             0.87                                                          Propylene Glycol                                                                              1.75                                                          Preservative**  0.10                                                          ______________________________________                                         *VINOL 540 which is supplied by Air Products and Chemicals, Inc. for a        partially hydrolyzed polyvinyl alcohol having a high viscosity and a          percent hydrolysis of 87% to 98%.                                             **KATHON LX 1.5 which is a mixture of                                         5chloro-2-methyl-4-isothiazolin-3-one and 2methyl-4-isothiazolin-3-one        which is supplied by Rohm and Haas Co.                                   

The blue dye, defoamer and CMC used in EXAMPLE 3 were the same as thatof EXAMPLE 1.

EXAMPLE 4

This example illustrates the formula of a composition of this inventionwhich contains a substantial quantity of polyvinylpyrroliodine.

    ______________________________________                                        Ingredient         Parts By Weight                                            ______________________________________                                        Deionized Water    83.51                                                      Defoamer           0.25                                                       Polyvinyl alcohol  6.67                                                       CMC                1.00                                                       Polyvinylpyrrolidone*                                                                            6.66                                                       Propylene Glycol   1.75                                                       Blue dye           0.01                                                       Ethyl parahydroxybenzoate                                                                        0.05                                                       Benzoic acid       0.10                                                       ______________________________________                                         *LUVISCOL K90 which is supplied by B.A.S.F. Akhengesellschaft.           

The adhesive gel of this EXAMPLE 4 had a viscosity of 35,000 cps at 2RPM and 20,000 cps at 2 RPM when measured by use of a Brookfield RVFviscometer at 25° C. with a No. 6 spindle. The thixotropic index was1.75 and the wet tack was 250 g per square inch. The polyvinyl alcohol,CMC, and blue dye were the same as that used in EXAMPLE 1.

EXAMPLE 5

This example illustrates a composition of this invention which usedxanthan gum as the thickening agent polymer.

    ______________________________________                                        Ingredient         Parts By Weight                                            ______________________________________                                        Deionized water    83.51                                                      Blue dye           0.01                                                       Polyvinyl alcohol  13.33                                                      Xanthan gum.sup.1  1.00                                                       Defoamer           0.25                                                       Ethyl parahydroxybenzoate                                                                        0.05                                                       Benzoic acid       0.10                                                       Propylene glycol   1.75                                                       ______________________________________                                         .[.KELAZAN,.]. .Iadd.KELZAN,.Iaddend. an industrial grade xanthan gum         supplied by the Kelco Division of Merck & Co.                            

The gel of EXAMPLE 5 had a viscosity of 62,000 cps and 13,500 cps for athixotropic index of about 4.6. The viscosity was measured at 25° C. byuse of a Brookfield RVF viscometer with a No. 6 spindle. This producthad a wet tack of 400 grams per square inch.

EXAMPLE 6

This example shows the use of sodium alginate as the thickening agentpolymer for preparing a gel adhesive of this invention. The remainingingredients are the same as those used in EXAMPLE 1.

    ______________________________________                                        Ingredient         Parts By Weight                                            ______________________________________                                        Deionized water    83.51                                                      Blue dye           0.01                                                       Polyvinyl alcohol  13.33                                                      Sodium alginate*   1.00                                                       Defoamer           0.25                                                       Ethyl parahydroxybenzoate                                                                        0.05                                                       Benzoic acid       0.10                                                       Propylene glycol   1.75                                                       ______________________________________                                         *KELGIN MV which is supplied by the Kelco Division of Merck & Co.        

The gel of this EXAMPLE 6 had a viscosity of 35,000 cps and 23,000 cpswhen measured at 2 RPM and at 20 RPM respectively with a Brookfield RVFviscometer at 25° C. using a No. 6 spindle. It had a thixotropic indexof about 1.5 and a wet tack of 335 g per square inch.

EXAMPLE 7

This example shows incompatibility of hydroxypropyl methylcellulose asthe thickening agent polymer.

This formulation was unsatisfactory since a thick layer of the.[.hydroxypropyl/methlcellulose.]. .Iadd.hydroxypropyl methylcellulose.Iaddend.separated and formed on top of the sample.

    ______________________________________                                        Ingredient           Parts by Weight                                          ______________________________________                                        Deionized water      83.51                                                    FD&C No. 1 (2% aqueous solution)                                                                   0.01                                                     Polyvinyl alcohol    13.33                                                    Hydroxypropyl methylcellulose*                                                                     1.00                                                     Defoamer             0.25                                                     Ethyl parahydroxybenzoate                                                                          0.05                                                     Benzoic acid         0.10                                                     Propylene glycol     1.75                                                     ______________________________________                                         *METHOCEL K 15 MS which is supplied by the Dow Chemical Co. Apart from th     hydroxypropyl methylcellulose, the remaining ingredients were the same as     that of EXAMPLE 1.                                                       

EXAMPLE 8

The substitution of hydroxyethyl cellulose for the hydroxypropylmethylcellulose of the formulation in EXAMPLE 7 also gave unsatisfactoryresults since a thick layer of the hydoxyethyl cellulose separated outof the formula.

What is claimed is:
 1. An article of .[.manufacturing.]..Iadd.manufacture .Iaddend.comprising:A. a flexible dispenser whereinthe dispenser has a dispensing opening of from about .[.0.011 to 0.12.]. .Iadd.0.0028 to about 0.018 .Iaddend.square inches and contains aclear adhesive gel which can be dispensed therefrom by finger-pressureto form a glue line which does not run when extruded on paper in avertical position; B. said clear adhesive gel comprising:(1) about 70%to 93% of water; (2) about 5% to 25% of a partially hydrolyzed polyvinylalcohol: (3) about 0.5% to 3% of a water soluble plasticizer for thepolyvinyl alcohol; (4) a water soluble defoamer in an amount sufficientto prevent air bubbles from destroying the clarity of the gel; and (5) awater soluble thickening agent polymer compatible with the polyvinylalcohol and in an amount sufficient to provide the gel with athixotropic index of about 1.5 to 4.5, said thickening agent selectedfrom the group consisting of sodium carboxymethylcellulose, sodiumalginate and xanthan gum.
 2. The article of claim 1 wherein thedispenser has a dispensing opening of from 0.06 to 0.15 inches indiameter.
 3. The article of claim 2 which consists essentially of: 75%to 93% water; 5% to 20% of polyvinyl alcohol; 0.5% to 1.5% of thethickening agent: 0.5% to 3% of the plasticizer; and 0.05% to 0.35% ofthe defoamer.
 4. The article of claim 2 wherein the portion of thedispenser with the gel contained therein is transparent.
 5. The articleof claim 2 wherein .Iadd.the plasticizer is a member selected from thegroup consisting of .Iaddend.propylene glycol, glycerol, ethyleneglycol, and diethylene glycol.
 6. The article of claim 2 whereto the gelcan be laundered out of clothing in hot or cold water after .[.is.]..Iadd.it .Iaddend.has dried.
 7. The article of claim 2 wherein the gelhas a wet tack of at least 225 grams per square inch and a time of setof about 16 to 35 seconds at 25° C. and a relative humidity of 35%. 8.The article of claim 1 wherein the flexible dispenser is a clear bottle.9. The article of claim 1 wherein the flexible dispenser is a cleartube.
 10. The article of claim 2 wherein the dispenser has a dispenseropening of from 0.07 to 0.10 inches in diameter.
 11. The article ofclaim 1 wherein the thickening agent is xanthan gum.
 12. An article ofmanufacture comprising:A. a clear flexible plastic dispenser wherein thedispenser has a dispensing opening .[.if.]. .Iadd.of .Iaddend.from about.[.0.011 to 0.12 .]. .Iadd.0.0028 to about 0.018 .Iaddend.square inchesand contains a clear adhesive gel which can be dispensed therefrom byfinger-pressure to form a glue line which does not run when extruded onpaper in a vertical position: B. clear adhesive gel comprising of:(1)about 70% to 93% of water: (2) about 5% to 25% of a partially hydrolyzedpolyvinyl alcohol: (3) about 0.5% to 3% of a water soluble plasticizerfor the polyvinyl alcohol; (4) a water soluble defoamer in an amountsufficient to prevent air bubbles from destroying the clarity of thegel; and .[.(50 .]. .Iadd.(5) .Iaddend.about 0.5% to 1.5% of a watersoluble thickening .[.agnet.]. .Iadd.agent .Iaddend.polymer compatiblewith the polyvinyl alcohol to impart a thixotropic index to the gel ofabout 1.5 to 4.5, said thickening agent selected from the groupconsisting of sodium carboxymethylcellulose, sodium alginate and xanthangum.
 13. The article of claim 12 wherein the dispensing opening has adiameter of 0.07 to 0.10 inches.
 14. The gel of claim 13 wherein thethickening agent is xanthan gum.
 15. The gel of claim 13 wherein fromabout 5% to 50% of the polyvinyl alcohol is replaced withpolyvinylpyrrolidone.
 16. The gel of claim 13 wherein the quantity ofwater is from about 75% to 93% by weight of the gel and the polyvinylalcohol is from about 5% to 20% by weight of the gel.